The compound 4-{[(2R, 3S,4R,5S)-4-(4-Chloro-2-Fluoro-Phenyl)-3-(3-Chloro-2-Fluoro-Phenyl)-4-Cyano-5-(2,2-Dimethyl-Propyl)-Pyrrolidine-2-Carbonyl]-Amino}-3-Methoxy-Benzoic Acid is represented by formula (1)

The compound of formula (1), or compound (1), as well as methods for making it, are disclosed in U.S. Pat. No. 8,354,444 and WO2011/098398.
4-{[(2R,3S,4R,5S)-4-(4-Chloro-2-fluoro-phenyl)-3-(3-chloro-2-fluoro-phenyl)-4-cyano-5-(2,2-dimethyl-propyl)-pyrrolidine-2-carbonyl]-amino}-3-methoxy-benzoic acid (C31H29Cl2F2N3O4) is a potent and selective inhibitor of the p53-MDM2 interaction that activates the p53 pathway and induces cell cycle arrest and/or apoptosis in a variety of tumor types expressing wild-type p53 in vitro and in vivo. Compound (1) belongs to a novel class of MDM2 inhibitors having potent anti-cancer therapeutic activity, in particular in leukemia such as acute myeloid leukemia (AML) and solid tumors such as for example head and neck, non-small cell lung, breast and colorectal cancers, as well as sarcoma.
The above-identified international patent application and US Patent describe Compound A in crystalline form and is herein incorporated by reference in its totality. The crystalline form of the compound has an on-set melting point of approximately 277° C. The crystalline forms have relatively low aqueous solubility (<0.05 μg/mL in water) at physiological pHs (which range from pH1.5-8.0) and consequently less than optimal bioavailability (high variability). It is thus desirable to obtain a form of the compound which has improved solubility/dissolution rate and bioavailability.
Active pharmaceutical ingredients (API's) may be prepared in a variety of different forms, such as for example salts, solvates, hydrates, co-crystals. API's may also be in their amorphous state or one or several crystalline forms (polymorphs). Depending on the form, the physicochemical properties of an API may change, leading to e.g. different solubility, thermodynamic stability, density or melting point of different forms. Such physicochemical properties therefore may have significant influence of the efficacy or bioavailability of a known API.